cope with potentially long ->d_dname() output for shmem/hugetlb

dynamic_dname() is both too much and too little for those - the
output may be well in excess of 64 bytes dynamic_dname() assumes
to be enough (thanks to ashmem feeding really long names to
shmem_file_setup()) and vsnprintf() is an overkill for those
guys.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 12 insertions, 7 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 87bdb5329c3c..83cfb834db03 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2724,6 +2724,17 @@ char *dynamic_dname(struct dentry *dentry, char *buffer, int buflen,
         return memcpy(buffer, temp, sz);
 }
 
+char *simple_dname(struct dentry *dentry, char *buffer, int buflen)
+{
+        char *end = buffer + buflen;
+        /* these dentries are never renamed, so d_lock is not needed */
+        if (prepend(&end, &buflen, " (deleted)", 11) ||
+            prepend_name(&end, &buflen, &dentry->d_name) ||
+            prepend(&end, &buflen, "/", 1))  
+                end = ERR_PTR(-ENAMETOOLONG);
+        return end;  
+}
+
 /*
  * Write full pathname from the root of the filesystem into the buffer.
  */
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 34423978b170..d19b30ababf1 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -926,14 +926,8 @@ static int get_hstate_idx(int page_size_log)
         return h - hstates;
 }
 
-static char *hugetlb_dname(struct dentry *dentry, char *buffer, int buflen)
-{
-        return dynamic_dname(dentry, buffer, buflen, "/%s (deleted)",
-                                dentry->d_name.name);
-}
-
 static struct dentry_operations anon_ops = {
-        .d_dname = hugetlb_dname
+        .d_dname = simple_dname
 };
 
 /*